The purpose of this study is to examine the circadian heart rate and blood pressure patterns in an elderly population with cardiovascular disease to provide data that will improve the timing of cardiovascular nursing assessments. The specific research questions are: Do heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) in an elderly population with cardiovascular disease follow circadian patterns? Are patterns of HR, SBP, and DBP in an elderly population with cardiovascular disease different from circadian rhythms in an elderly population without cardiovascular disease? What is the most appropriate time of day to obtain routine measures of SBP, DBP, and HR in an elderly population with cardiovascular disease? A two group design will compare elderly subjects (ages 65-99) with chronic congestive heart failure on digoxin therapy to a healthy control group matched for age and gender. Twenty subjects will be in each group. The variables to be studied will be systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) measured every two hours while awake for two consecutive days. Data on rest-activity patterns and medication profiles will be collected. Individual and group cosinor analysis using the least squares method will be conducted, and the rhythmometric parameters of acrophase (time of peak value), mesor (average value for the rhythm) and amplititude (difference between peak value and mesor) will be obtained for SBP, DBP, and HR. Group comparison will be conducted with Hotelling's T2, and rest-activity data will be analyzed in conjunction with the SBP, DBP, & HR curves. This study will provide important data on 24-hour fluctuations of SBP, DBP, & HR in the elderly with cardiovascular disease and will contribute to nursing science by delineating timing for more accurate cardiovascular assessments.